The present invention relates to a lubrication system for use in manual transmissions.
As is known, manual transmissions are used in a plethora of motor vehicle applications for transmitting rotary power (i.e., drive torque) from an input shaft to one or more output shafts at various speed ratios. To provide the desired speed ratios, a number of constant mesh gearsets are supported on the shafts, with a drive gear fixed to one shaft and a driven gear rotatably supported on the other shaft. A suitable clutch arrangement is provided for permitting the driven gear of the gearset to be coupled to its shaft for transmitting rotary power thereto. Transmissions generally include a housing within which the rotary components of the transmission are disposed and a lubrication system for supplying lubricating fluid to the rotary components.
In many instances, the transmission is constructed such that the lubrication system delivers oil from an internal reservoir or sump area within the housing to an axial cavity formed in each shaft which, in turn, communicates with a series of radially-extending passages for directing the flow of oil to the shaft surface and/or bearings supporting the driven gear so as to provide lubrication thereto. Such oil lubrication systems typically includes a passageway formed in the housing for directing oil from the reservoir to an oil cap mounted in the axial cavity in each rotating shaft. Traditionally, the oil flowing to the oil cap is exposed to several of the rotary components of the transmission. This is problematic in that the centrifugal forces generated by such rotary components tend to drive the oil back toward the passageway, thereby decreasing the flow efficiency of the oil supply.
In view of the above, a continuing need exists to address the problems associated with the oil flow characteristics provided by conventional oil caps.